Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series / Известия Национальной академии наук Беларуси. Серия физико-технических наук
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ИСТОЧНИК ЗАХВАТНОГО ГАММА-ИЗЛУЧЕНИЯ С ЭНЕРГИЯМИ ДО 7 МэВ И ДО 10 МэВ НА ОСНОВЕ ПОВЕРОЧНОЙ УСТАНОВКИ НЕЙТРОННОГО ИЗЛУЧЕНИЯ
Get PDFWide spread of technogenic sources of ionizing radiation such as particle accelerators and nuclear reactors leads to appearance of a number of applied metrological tasks aimed at providing spectrometric and dosimetric ionization measurement instruments, located in photon radiation fields with energy to 10 MeV. Gamma rays with energy higher 3 MeV may be acquired using radioactive thermal neutron capture on target, i.e. (n, γ)-nuclear reaction. Titanium is used in the range of energies to 7 MeV; nickel – to 10 MeV. A simplest source of instantaneous neutron capture gamma-ray should consist of fast neutron source, neutron moderator and a target irradiated with thermal neutrons. The collimator with thermal neutron geometry of АТ140 neutron calibration facility with 238Pu–Be fast neutron source may be used (IBN–8–6) as a source of gamma-ray with energy to 10 MeV. Monte-Carlo models of thermal neutrons geometry, facility and 238Pu–Be fast neutron source were built using MCNP–4b code. Energy distribution of flux density of neutron capture gamma–ray for titanium and nickel targets was defined. A spectrometric detector based on LaBr3(Ce) crystal Ø 38×38 mm with non-linear characteristics of channel-energy transformation in the range up to 10 MeV, was specifically manufactured for instrumental support of the experiment at SPE “ATOMTEX”. The results for Ti, Ni, and for bare 238Pu–Be neutron source were acquired. During the experiment a possibility to use neutron capture gamma-ray field formed by thermal neutrons geometry of АТ140 neutron calibration facility with 238Pu–Be-fast neutron source with Ti and Ni targets for calibration LaBr3(Ce) spectrometers for energy to 10 MeV was confirmed. Closely stationing polyethylene plate in collimator channel provides significant increase in output of reference radiation from target simultaneously decreasing unneeded parts of the spectrum.
ОСОБЕННОСТИ СИНТЕЗА МНОГОСЛОЙНЫХ СТРУКТУР НА ОСНОВЕ ЭЛЕКТРОЛИТИЧЕСКИ ОСАЖДЕННЫХ ПЛЕНОК НИКЕЛЬ-ЖЕЛЕЗО И ЭФФЕКТИВНОСТЬ ИХ РАДИАЦИОННОЙ ЗАЩИТЫ
Get PDFModern semiconductor devices and microchips are sensitive to the effects of ionizing radiation. Nevertheless, they are widely used in military and space technology, in the nuclear industry. At the same time, a number of technological, circuit and software solutions are used to reduce the effects of radiation exposure. The most preferable method is one based on using shields, due to its low cost and excellent radiation properties of shield’s materials. Recently, special attention has been paid to the study of multilayer structures. Experimental samples of Ni-Fe alloys and multilayer Ni-Fe/Cu structures with different chemical composition were obtained by electrochemical deposition. The dependence of chemical composition variation from deposition conditions was determined. Ni-Fe alloys crystal structure was studied using X-ray diffraction. Shielding properties of Ni-Fe/Cu multilayer structures were investigating on linear accelerator ELA-4 under 4 MeV electron irradiation. Silicon p-MOSFETs were used as test structures. Evaluation of electron flow weakening effectiveness was performed by current-voltage characteristics changing – threshold voltage of pMOS-transistors, which were located behind shields based on NiFe/Cu multilayered structures and without shields. It was found that increasing number of Ni-Fe layers within the same total thickness leads to maximum shielding efficiency
ДИФФУЗИЯ И МАГНИТОФОРЕЗ В НАНОДИСПЕРСНЫХ МАГНИТНЫХ ЖИДКОСТЯХ С ФАЗОВЫМ ПЕРЕХОДОМ
Get PDFA description of mass transfer processes in nanodispersed magnetic suspensions (magnetic fluids) is proposed under the assumption that assembly of magnetic particles in them can exist in the form of two phases: gaseous and condensed, and the phase transitions are determined by well-known thermodynamic conditions of phase equilibrium and depend on concentration of particles and magnetic field intensity. The distribution of concentration of magnetic particles in a gas phase conforms the diffusion equation, and in the condensed phase it is supposed to be constant. Process is described by the dimensionless magnetic parameter representing the relation of magnetic energy of a particle to thermal one, and also by the parameter characterizing dipole-dipole interaction between particles. The analytical solution to one-dimensional problem on distribution of concentration of particles in a magnetic fluid in locally non-uniform magnetic field is presented on the basis of the equations of diffusion and phase equilibrium. It is shown, that phase transition at given average concentration of particles is observed when the magnetic parameter exceeds certain value, and the area of the condensed phase increases with its increasing. At its large values the coordinate of phase transition boundary depends on average concentration of particles in the considered problem practically linearly
АЛГОРИТМЫ ОБРАБОТКИ ДАННЫХ, ПОЛУЧАЕМЫХ С ДАТЧИКОВ ДАВЛЕНИЯ ГИДРОЦИЛИНДРОВ ЗАБОЙНЫХ КРЕПЕЙ
Get PDFAlgorithms to analyze data produced by pressure sensors mounted on hydraulic cylinders of mine linings, which are exploited in lavas of the Starobin potash deposit, are presented. To build algorithms, data mining process has been represented by three general stages. First of them consists of data preprocessing. Based on data specifics, algorithms of removing outliers as well as determining characteristics independent of tunneling machine location and state of bottomhole supports were included in it. The second stage contains algorithms of finding in the preprocessed data of cycles, which were created by descent of mining supports, and phases of cycles that depend on location of the tunneling machine relative to those supports. Algorithms of the third stage were built to compute data characteristics connected with the found cycles and their phases. Besides, modifications of correlation algorithms for aggregated data were developed in order to investigate relationship between the characteristics, including their coupling with behavior of rock pressure. The algorithms are designed for use in automated monitoring systems of rock pressure in lavas of potash mines, including mines of the Joint Stock Company “Belaruskali”. The developed algorithms were programmed. Program realizations were seriously tested on big data supplied by pressure sensors mounted on hydraulic cylinders of bottomhole supports of the Starobin potash deposit. As an example of application of the developed algorithms, it is shown that acceleration of mining process increases the likelihood of rock blows to the supports
МАГНИТОСТРИКЦИОННЫЙ МЕХАНИЗМ ОБРАЗОВАНИЯ МЕЛКОДИСПЕРСНОЙ СТРУКТУРЫ В СТАЛЬНЫХ ИЗДЕЛИЯХ ПРИ МАГНИТНО-ИМПУЛЬСНОМ ВОЗДЕЙСТВИИ
Get PDFIt is established that in magneto static fields, which can really be used in industrial equipment, the magnitude of electromagnetic energy is not sufficient for phase equilibrium changing. However, in pulse magnetic field, ones can obtain the changing of phase equilibrium for surface layer of ferromagnetic work material. The thickness of material layers is comparable with skin depth. It is shown, that the magnetic-pulse action on ferromagnetic sample surface provides conditions for formation of small-dispersed structure when the temperature approaches to the Curie temperature. In the presence of strong magnetic field, deformations of ferromagnetic regions arise due to magnetostriction, which are displaced relative to paramagnetic regions localized near the grain and domain boundaries. It leads to a disintegration of ferrite grains and to formation of an anisotropic structure since the regions with specific orientation of crystal planes are disintegrated by magnetostriction.Показано, что при магнитно-импульсном воздействии на ферромагнитный образец реализуются условия, способствующие образованию мелкодисперсной структуры при приближении температуры поверхности образца к температуре Кюри. При наличии сильного магнитного поля вследствие магнитострикции происходит деформация ферромагнитных участков, которые сдвигаются относительно парамагнитных областей, локализованных вблизи границ зерен и границ доменов. В результате возникающих механических напряжений может происходить дробление зерен. Магнитострикция приводит не только к измельчению зерен феррита, но и к образованию упорядоченной структуры, поскольку дроблению подвергаются участки с определенной ориентацией кристаллических плоскостей
ЗАКОНОМЕРНОСТИ ВЛИЯНИЯ ТЕХНОЛОГИЧЕСКОГО ПРОЦЕССА ПОДГОТОВКИ И СБОРКИ ПОД СВАРКУ НА ФОРМИРОВАНИЕ БЕЗДЕФЕКТНЫХ СВАРНЫХ СОЕДИНЕНИЙ
Get PDFJoint preparation (root face), overmatched size of the gap, bad fit-up, misalignment, not completed removal of rust, oil and incorrect tack welds are main factorial parameters. Experiments were carried out to confirm theoretical results and to establish schematics of defects, which were formed in production welds when dominated factors were negative. Research as conducted during construction of technological pipelines of different size with shielded arc welding (SAW), GMAW in CО2 and Ar + CО2 and GTAW. Welding was performed at certified production welding laboratories in accordance with tasks of the State Programs in scientific research. Results confirmed data from previous study in statistical analyzing of defects occurring. It is concluded that negative factors of joint preparation are the cause of forming of defects structure which is unique, related to this only factor.
ГИДРООБЪЕМНО-МЕХАНИЧЕСКИЕ ТРАНСМИССИИ МОБИЛЬНЫХ МАШИН. РАСЧЕТ КИНЕМАТИЧЕСКИХ И СИЛОВЫХ ПАРАМЕТРОВ
Get PDFУПРАВЛЕНИЕ ОБРАБОТКОЙ ПОВЕРХНОСТЕЙ ДЕТАЛЕЙ МАШИН В ПРОЦЕССАХ МАГНИТНО-ЭЛЕКТРИЧЕСКОГО УПРОЧНЕНИЯ И МАГНИТНО-АБРАЗИВНОЙ ОБРАБОТКИ
Get PDFThe influence of nature of magnetic field on processes of magnetic-electric hardening and magnetic-abrasive machining of machine parts is examined. Modes of magnetic-electric hardening are set in order to obtain the highest process stability. A scheme of magnetic-abrasive machining is offered to intensify the process by regenerating the ferro-abrasive brush.Рассматривается влияние характера магнитного поля на процессы магнитно-электрического упрочнения и магнитно-абразивной обработки деталей машин. Установлены режимы магнитно-электрического упрочнения для получениянаибольшей стабильности процесса. Предложена схема магнитно-абразивной обработки с целью интенсификации процесса путем регенерации ферроабразивной щетки